Pipe shut-off devices for the emergency supply of coolant to the fuel rods arranged in a reactor vessel of a nuclear power plant with coolant are known. In this respect, a shut-off device is provided in the pipeline and has the following configuration. A pivotable check valve is arranged in the pipeline and is a component of the pipe shut-off device. The pivot axis of the check valve has a lever arm, with a weight being arranged at the end of the lever arm. The weight is held by a rope or by a chain in a position in which the check valve shuts off the pipeline. Provision is made on an incipient core meltdown that this chain or the rope melts, the weight moves downward due to gravity and in so doing the check valve of the pipe shut-off device is opened against the applied coolant. This design of such a pipe shut-off device has various disadvantages. Boron-treated water serves as the coolant for the reactor vessel. The pivotable check valve is seated under the pressure of the applied coolant and of the weight in the closed state of the valve on a metal flat seal arranged in the pipe section of the pipe shut-off device. Boron-treated water is extremely aggressive toward metals so that the boron-treated water attacks the metal seal over the course of time. This can result in leaks, so a reservoir is provided in the region of the shut-off device to receive the leak liquid. In order to be able to ensure leaktightness in the long term, recurring checks are required at fixed, brief time intervals. Such checks of the function of the check valve are complex and/or expensive; a further shut-off valve having an electric drive is located in front of the check valve in the direction of flow. It has to be closed for the check in order to drain and dispose of the coolant present between the shut-off valve and the check valve in a controlled manner. Subsequent hereto, the function of the check valve is tested, with here the rope or the chain being released which holds the check valve in a closed position against the force of the weight. Not only the high service effort is a disadvantage with this shut-off device, but also the asymmetrical arrangement of the check valve at the neutral axis, which is problematic in dynamic load cases. High opening forces are furthermore required since the valve has to be opened against the dynamic pressure of the coolant. It is furthermore disadvantageous that this pipe shut-off device comprises a number of individual parts which make such a shut-off device very expensive.
Furthermore, a pipe shut-off device is known in which a valve disk is rotatably supported in a pipe section by an electrical drive. So-called soft seals are provided in this respect which have the disadvantage that they are not age-resistant. This means that brief service intervals are also provided here. A leak container is also provided here despite the close service intervals.